CVE-2025-21722

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

nilfs2: do not force clear folio if buffer is referenced

Patch series "nilfs2: protect busy buffer heads from being force-cleared".

This series fixes the buffer head state inconsistency issues reported by

syzbot that occurs when the filesystem is corrupted and falls back to

read-only, and the associated buffer head use-after-free issue.

This patch (of 2):

Syzbot has reported that after nilfs2 detects filesystem corruption and

falls back to read-only, inconsistencies in the buffer state may occur.

One of the inconsistencies is that when nilfs2 calls mark_buffer_dirty()

to set a data or metadata buffer as dirty, but it detects that the buffer

is not in the uptodate state:

WARNING: CPU: 0 PID: 6049 at fs/buffer.c:1177 mark_buffer_dirty+0x2e5/0x520

fs/buffer.c:1177

...

Call Trace:

<TASK>

nilfs_palloc_commit_alloc_entry+0x4b/0x160 fs/nilfs2/alloc.c:598

nilfs_ifile_create_inode+0x1dd/0x3a0 fs/nilfs2/ifile.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References